libext2fs documentation

After a repartition and (win95) reformat I find I didn't save away all the data
I wanted from an ext2 fs, so I've spent a morning grovelling through the source
and figuring out the structure. (I think I can get the data back, only the first
block group got overwritten by format)

Now I find that libext2fs exists.. is there any documentation on how to use it,
and how much does it depend on the filesystem being intact? Can it be told to
use a backup superblock? I discovered that mount(8) can be given an option to
do so, but the utilities (e2fsck, debugfs etc) don't seem to, so is it some
limitation of libext2fs?